elf/tst-tls-ie-dlmopen.c

   1 /* Test dlopen of modules with initial-exec TLS after dlmopen.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This test tries to check that surplus static TLS is not used up for
  20    dynamic TLS optimizations and 4*144 = 576 bytes of static TLS is
  21    still available for dlopening modules with initial-exec TLS after 3
  22    new dlmopen namespaces are created.  It depends on rtld.nns=4 and
  23    rtld.optional_static_tls=512 tunable settings.  */
  24
  25 #include <errno.h>
  26 #include <pthread.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 static int do_test (void);
  32 #include <support/xthread.h>
  33 #include <support/xdlfcn.h>
  34 #include <support/check.h>
  35 #include <support/test-driver.c>
  36
  37 /* Have some big TLS in the main exe: should not use surplus TLS.  */
  38 __thread char maintls[1000];
  39
  40 static pthread_barrier_t barrier;
  41
  42 /* Forces multi-threaded behaviour.  */
  43 static void *
  44 blocked_thread_func (void *closure)
  45 {
  46   xpthread_barrier_wait (&barrier);
  47   /* TLS load and access tests run here in the main thread.  */
  48   xpthread_barrier_wait (&barrier);
  49   return NULL;
  50 }
  51
  52 static void *
  53 load_and_access (Lmid_t lmid, const char *mod, const char *func)
  54 {
  55   /* Load module with TLS.  */
  56   void *p = xdlmopen (lmid, mod, RTLD_NOW);
  57   /* Access the TLS variable to ensure it is allocated.  */
  58   void (*f) (void) = (void (*) (void))xdlsym (p, func);
  59   f ();
  60   return p;
  61 }
  62
  63 static int
  64 do_test (void)
  65 {
  66   void *mods[5];
  67
  68   {
  69     int ret = pthread_barrier_init (&barrier, NULL, 2);
  70     if (ret != 0)
  71       {
  72         errno = ret;
  73         printf ("error: pthread_barrier_init: %m\n");
  74         exit (1);
  75       }
  76   }
  77
  78   pthread_t blocked_thread = xpthread_create (NULL, blocked_thread_func, NULL);
  79   xpthread_barrier_wait (&barrier);
  80
  81   printf ("maintls[%zu]:\t %p .. %p\n",
  82            sizeof maintls, maintls, maintls + sizeof maintls);
  83   memset (maintls, 1, sizeof maintls);
  84
  85   /* Load modules with dynamic TLS (use surplus static TLS for libc
  86      in new namespaces and may be for TLS optimizations too).  */
  87   mods[0] = load_and_access (LM_ID_BASE, "tst-tls-ie-mod0.so", "access0");
  88   mods[1] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod1.so", "access1");
  89   mods[2] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod2.so", "access2");
  90   mods[3] = load_and_access (LM_ID_NEWLM, "tst-tls-ie-mod3.so", "access3");
  91   /* Load modules with initial-exec TLS (can only use surplus static TLS).  */
  92   mods[4] = load_and_access (LM_ID_BASE, "tst-tls-ie-mod6.so", "access6");
  93
  94   /* Here 576 bytes + 3 * libc use of surplus static TLS is in use so less
  95      than 1024 bytes are available (exact number depends on TLS optimizations
  96      and the libc TLS use).  */
  97   printf ("The next dlmopen should fail...\n");
  98   void *p = dlmopen (LM_ID_BASE, "tst-tls-ie-mod4.so", RTLD_NOW);
  99   if (p != NULL)
 100     FAIL_EXIT1 ("error: expected dlmopen to fail because there is "
 101                 "not enough surplus static TLS.\n");
 102   printf ("...OK failed with: %s.\n", dlerror ());
 103
 104   xpthread_barrier_wait (&barrier);
 105   xpthread_join (blocked_thread);
 106
 107   /* Close the modules.  */
 108   for (int i = 0; i < 5; ++i)
 109     xdlclose (mods[i]);
 110
 111   return 0;
 112 }